Humans have relied on wood for heat ever since Prometheus stole fire from the gods. Only in the last century have we moved away from it in the developed world. Environmentalists tell us that we can never go back. Global forests are dwindling, wood smoke releases greenhouse gases and fine particulate that fouls the air in built-up areas. In some cities like Montreal, regulations now ban the use of wood stoves and fireplaces in new construction.
Unsettling news for anyone who believes that nothing warms the backside in January like the heat from a wood stove or a blazing fireplace. The ritual of gathering winter wood is one of the oldest traditions of country life. But can we continue to roast chestnuts by an open fire in good conscience if it releases carbon to the atmosphere and a list of toxic chemicals that include benzene, formaldehyde, acrolein and polycyclic aromatic hydrocarbons (PAHs)?
The answer is a qualified ‘yes.’
Climate change and the environment
Burning wood is carbon neutral where forests are sustainable. All wood eventually releases its carbon whether it burns in a few hours or rots over a number of years. Robert Frost captured it neatly when he talked about “the slow smokeless burning of decay.” When cellulose breaks down in the natural world it takes oxygen from the atmosphere and converts it to carbon. But both wood burning and decay are still carbon neutral if a forest is allowed to regenerate. As the forest regrows it gives off oxygen and sequesters carbon. It makes sense to use the heat from dead, diseased and less valuable species and keep growing new trees.
The World Energy Council estimates that biomass accounts for between 10 and 15 per cent of the world’s energy use, compared to 75-80 per cent for fossil fuels. Wood makes up the largest share of biomass fuel and many developing countries still rely heavily on it. That share is growing as new technologies deliver more efficient and cleaner methods for burning biomass fuels. But many environmental groups object to burning biomass for energy because it contributes to carbon emissions and depletes the planet’s dwindling forest reserves. They would prefer the world move to other forms of renewable energy such as solar and wind power.
Twenty million hectares or roughly 10 per cent of all forest land suitable and available for commercial use in Canada is in the hands of private woodlot owners. The natural progress of wildfires destroys that amount of forest in Canada every decade. In spite of occasional spikes, the number of wildfires and the area burned remains relatively constant from year to year. Wildfires are generally accepted to be part of the forest’s natural cycle and remain a minor source of carbon release — only 4-6 per cent in comparison to the 85 per cent released by burning fossil fuels.
Obviously, if all communities relied on wood for heat, the world’s forests would soon disappear and their buffering capacity to absorb carbon would be lost. But wood-burning is a classic local issue. Judging the morality of your wood stove based on global forest health is the same logic that comedian Allan Sherman’s mother used when she scolded him to clean his plate because children were starving in Africa. Sherman did as he was told, but “the children kept starving and I got fat.” Burning wood from a sustainably managed forest is sensible and practical and poses no threat to global forests. Cleaning up trash and combustibles on the forest floor reduces the risk of wildfire. If you want to be totally carbon neutral, you could use a cross-cut saw and a wheelbarrow.
Air Pollution
Particulate emissions from wood are a legitimate concern for built-up areas. Wood smoke adds to urban air quality problems and during temperature inversions can seriously affect people with breathing difficulties. That’s the main reason behind the push in urban North America to reduce the use of wood stoves and fireplaces. In 2015, the U.S. Environmental Protection Agency issued stricter emission standards for the manufacture and sale of new wood stoves, lowering particulate emission levels from the 1998 standard of 8.5 grams per hour to 4.5 grams. Existing stoves and fireplaces were not affected. The EPA plans to reduce the emission level even further to 2.0 grams by 2020. (There are very few products presently on the market that approach this level of purity and most of them are pellet stoves.)
The Canadian Standards Association closely follows EPA standards. Modern wood heaters and fireplaces burn very efficiently and, in the countryside, the emissions will float away and break down harmlessly over the landscape much as they have always done.
Safety
Another question is safety. Insurance companies are very vigilant about wood stoves and require policy owners to declare them, have them inspected and pay a premium for the increased risk. According to Fire Prevention Canada, chimney fires are not a leading cause of house fires. Cooking, smoking and unattended candles are the usual culprits and there is precious little a regulator can do except require the use of smoke detectors and circulate safety messages. The manufacture and use of candles in the home are not subject to any regulation at all. Statistics are scanty on the subject but Canadian Firefighter estimates chimney fires cause only about five per cent of house fires.
Best practices
Wood stoves are a lot of work. Not only does the wood have to hauled up and stacked, the stove itself has to be cleaned regularly and the whole family needs to take part in its management. Even the most efficient wood stove will not function properly if the fuel is not correctly seasoned. Firewood should have a moisture content of less than 20 per cent before it is ready for the stove. To achieve this level of dryness, most hardwoods like maple, oak, ash and beech should be cut in winter when sap levels are lowest, then split, stacked and covered for at least six months. Birch and poplar dry more quickly. Conifers, which have a different cell structure, take longer to season. There are some visible clues that tell you when wood is dry enough to burn. Look for radial checking and cracks in the end grain. Dry wood is lighter and two pieces banged together make a hollow sound, not a dull ‘thunk.’ The real test comes in the stove. Seasoned firewood will not leave dark patches on the glass or heavy creosote build-ups in the flue. Regular chimney cleanings should yield only a few cups of granular creosote the consistency of coarse sugar.
The Takeaway
Regulators, insurance companies and environmental groups always speak in general terms. But some of us live in very specific terms, far from the crowd, on a back road, sometimes off the grid entirely. For the small landholder, the case for a wood-burning stove is still very defensible. If you harvest firewood from a five acre woodlot on your property, season it correctly and put it through a wood burning appliance that meets EPA standards, you can burn the wood forever with a clear conscience. In fact, it beats virtually any other heat source option in an efficiency comparison and poses no more risk to your health or the environment than your propane barbecue does. Similarly, you could buy firewood from a neighbour who operates a sustainable woodlot.
The choice for the urban dweller is not so clear. In downtown Toronto and Vancouver, where air quality is already compromised, another contributor to particulate emissions will inevitably encounter resistance. The pressure for Montreal-style bans on wood-burning is only likely to increase and the experience of a wood fire in the family room will become a privilege open to a lucky few.
Last spring, I was sitting beside a wood stove in a cabin on a remote lake in the Algoma District of Northern Ontario with an old friend. He was telling me about the great fire that swept through the district in 1948, taking all the trees around this lake. He said it was only within the last ten years that the re-growth had finally erased the visible effects of that great fire. The cabin was now closely surrounded by trees and I asked if he worried that another fire might be due soon. He pointed out the window to a massive white pine that dated from the 1920s. The fire had gone around the lake but spared this tree and several others on the rocky point where the cabin stood. He made up his mind 45 years ago to keep company with this lucky pine tree and he feels his cabin is well-located. He has a ‘no-balsam rule’ because that species has a very high and explosive volatility. And he has pretty strict rules governing the use of his wood stove. But otherwise, he is content to enjoy the privilege he has to live and tread lightly in this corner of the woods.
The conversation reminded me that global pronouncements shouldn’t be ignored but they never guide us quite as reliably as local knowledge and our own observations. It was a chat made even more pleasant by our peaceful surroundings and the rosy glow from the wood fire in front of us.
- Dan Needles